Scala example source code file (LazyOptionTest.scala)

This example Scala source code file (LazyOptionTest.scala) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Scala by Example" ^TM.

Learn more about this Scala project at its project page.

Java - Scala tags/keywords

align, bindrec, cobind, equal, int, isempty, lazyoption, lazyoptiontest, monadplus, monoid, semigroup, speclite, traverse, zip

The LazyOptionTest.scala Scala example source code

package scalaz

import scalaz.scalacheck.ScalazProperties._
import scalaz.scalacheck.ScalazArbitrary._
import std.AllInstances._
import org.scalacheck.Prop.forAll

object LazyOptionTest extends SpecLite {
  checkAll(equal.laws[LazyOption[Int]])
  checkAll(bindRec.laws[LazyOption])
  checkAll(monadPlus.strongLaws[LazyOption])
  checkAll(cobind.laws[LazyOption])
  checkAll(traverse.laws[LazyOption])
  checkAll(zip.laws[LazyOption])
  checkAll(align.laws[LazyOption])
  checkAll(isEmpty.laws[LazyOption])
  checkAll(monoid.laws[LazyOption[Int]])

  "monoid" ! forAll { (a: LazyOption[Int], b: LazyOption[Int]) =>
    Monoid[LazyOption[Int]].append(a, b).toOption must_=== Monoid[Option[Int]].append(a.toOption, b.toOption)
  }

  "tail recursive tailrecM" in {
    val times = 10000

    val result =
      BindRec[LazyOption].tailrecM[Int, Int] {
        i => LazyOption.lazySome(if (i < 10000) \/.left(i + 1) else \/.right(i))
      }(0)
    result.getOrElse(0) must_=== times
  }

  object instances {
    def equal[A: Equal] = Equal[LazyOption[A]]
    def monadPlus = MonadPlus[LazyOption]
    def bindrec = BindRec[LazyOption]
    def cobind = Cobind[LazyOption]
    def traverse = Traverse[LazyOption]
    def zip = Zip[LazyOption]
    def align = Align[LazyOption]
    def isEmpty = IsEmpty[LazyOption]
    def monoid[A: Semigroup] = Monoid[LazyOption[A]]
  }
}